The Ecumene were an empire that also included allied races like the Ammonite. None were human. The Ecumene (at least the Ecumene themselves, not the allied species) were masters of physical law like the Vex, although clearly they operate as individuals like the Hive and humanity rather than like the computer collective mind of the Vex

The Ecumene’s race is still unknown at this point. I believe they are this council of multiple races looking over their little piece of the universe which is why they’ve grown to be so advanced

*Titan looked to a circle of warlocks, discussing mystery things* Huh? Oh, Warlocks discussing things in the tower again? *getting close to listen, then approach them after he heared a Strange word* Ecumene? What's that? *A female Warlock looks at him and explain their current topic* Aha, so you want to tell me that Ikoras researches found some Clovis Bray Informations about other lost Alien civilisations before our golden age ended? *She continues to explain the deep matter of their discussion to the titan* And they were highly advanced? Like the vex? Ok, that's hard to believe for me. Aand I think other Titans of my order will tell you the same. *The titan looks sarcastic then he continued serious* But hey, if that's true and they really existed, maybe they created the traveller and indirectly us... *All warlocks laugh except the female one. This reactions made the titan angry and he left the group* Tsss... Warlocks and their knowledge. *The female Warlock stopped looking at him and left also the Group. The comment of the titan gave her an idea.*